Techniques for inducing accelerated corrosion of steel in concrete

Corrosion of steel in concrete is a slow process. Due to the protective nature of concrete, it takes a reasonably long time for initiation and progress of reinforcement corrosion even in the case of severe corrosive exposure conditions. It is difficult to achieve a significant degree of reinforcement corrosion in a limited duration available for performing research studies evaluating (i) the loss of bond and loss of load-bearing capacity of corroding reinforced concrete members, (ii) the effect of mineral admixtures in reducing reinforcement corrosion, (iii) the performance of coated or alloyed reinforcing bars against reinforcement corrosion, and (iv) the effectiveness of electrochemical techniques applied for the prevention of reinforcement corrosion. For this reason, various techniques for inducing accelerated corrosion of steel in concrete are used by the researchers. In this paper, an attempt has been made to firstly describe the impressed current technique commonly used for accelerating reinforcement corrosion in small-as well as large-sized concrete specimens in the light of state-of-theart information available in the literature. Then the procedure for calculating degree of induced corrosion in percentage by mass and in terms of average corrosion current density using the intensity and duration of the applied current is presented. The effectiveness of the applied current in inducing reinforcement corrosion, guidelines for effectively using the impressed current technique, and some of the alternative techniques for inducing accelerated corrosion of steel in concrete are also described in the paper.